Wobble is inherent in the spider gene. Some snakes have it very mildly, others are so severe they have problems eating.
I have a few spider combos and they all wobble to an extent. Excitement/stress, such as at feeding time, seems to make it worse. I have one bumblebee female that gets so excited while eating that she will strike everywhere except where the rat is, so I have to feed her f/t and make sure the rat's nose is right in front of her nose so she can't miss it.
No one knows for certain whether or not the condition is painful, but I would expect it is not since the snakes all eat, shed, breed, etc. and are otherwise healthy.